THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 


AGRICULTURAL 
LIBRARY 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  210 


FIELD  INVESTIGATIONS  OF  FORAGE  POISON- 
ING IN  CATTLE  AND  HORSES 


H.  P.  RUSK  AND  II.  S.  GRTNDLKY 


UttRANA,  ILLINOIS,  JUNE,  1918 


SUMMARY  OF  BULLETIN  No.  210 

FEEDING  TESTS  WITH  CORN  SILAGE  SUSPECTED  OP  CAUSING  FORAGE  POISONING 
IN  CATTLE. — Numerous  outbreaks  of  forage  poisoning  in  cattle,  horses,  and  mules 
have  been  reported  to  the  University,  but  attempts  to  reproduce  the  disease  ex- 
perimentally in  cattle  by  feeding  suspected  or  .contaminated  feeds  have  been 
unsuccessful. 

The  results  of  these  investigations  seem  to  indicate  that  most  cattle  are  not 
so  susceptible  to  forage  poisoning  as  are  horses  and  mules,  and  that  contaminated 
corn  silage,  and  possibly  other  animal  feeds,  which  are  unsafe  or  fatal  to  horses, 
may  be  fed  with  less  danger  to  cattle.  Evidence  from  many  outbreaks  leads  to 
the  suggestion  that  some  cattle  may  be  more  susceptible  than  others,  and  that 
damaged  or  otherwise  contaminated  corn  silage,  and  possibly  other  feeds,  may  in 
some  instances  produce  fatal  results  in  cattle  following  ingestion.  Pages  163-169. 

REPORT  OF  FORAGE  POISONING  INVESTIGATIONS  WITH  HORSES  AT  OTTAWA, 
ILLINOIS. — Contaminated  corn  silage  from  the  McLean  silo  -near  Ottawa,  Illinois, 
induced  a  fatal  type  of  forage  poisoning  in  horses  following  ingestion.  The  most 
obvious  and  characteristic  symptoms  exhibited  by  the  horses  affected  in  this  ex- 
periment were  paralysis  of  the  throat,  profuse  salivation,  and  lack  of  muscular 
coordination. 

Prophylactic  doses  of  Botulinus  antitoxin  and  related  immune  sera,  developed 
by  Drs.  Graham,  Brueckner,  and  Pontius  at  the  University  of  Kentucky,  protected 
experimental  horses  against  the  effect  of  the  daily  ingestion  of  contaminated  corn 
silage  responsible  foa-  the  McLean  outbreak.  The  results  of  the  two  tests  at  the 
McLean  farm  apparently  justify  a  trial  of  these  sera  in  cases  of  similar  outbreaks. 

Pages  169-176. 

NOTE. — These  investigations  were  completed  before  the  Division  of  Animal 
Pathology  was  established.  They  were  continued  by  Dr.  Robert  Graham,  Chief  in 
Animal  Pathology.  All  communications  relating  to  forage  poisoning  should  be 
addressed  to  the  above  division. 


FIELD  INVESTIGATIONS  OF  FORAGE  POISON- 
ING IN  CATTLE  AND  HORSES 

BY  H.  P.  RUSK,  ASSISTANT  CHIEF  IN  CATTLE  HUSBANDRY,  AND 
H.  S.  GE1NDLEY,  CHIEF  IN  ANIMAL  NUTRITION 

During  recent  .years  an  increasing  number  of  inquiries  relative 
to  forage  poisoning  have  been  received  by  the  Department  of  Animal 
Husbandry  at  the  University  of  Illinois.  Many  of  these  inquiries 
regarding  outbreaks  in  herds  of  cattle  mentioned  corn  silage  as  a 
suspected  feed.  While  this  department  did  not  attempt  to  give  any 
authoritative  opinion  on  such  cases,  it  was  freely  conceded  that  our 
experience  would  not  lead  us  to  suspect  corn  silage  as  the  source  of 
trouble  in  outbreaks  of  forage  poisoning  among  cattle.  Common 
molds  found  on  silage  are  often  suspected  of  having  pathogenic 
properties,  but  specific  evidence  to  warrant  such  suspicion  is  want- 
ing. It  is  common  knowledge  that  in  most  cattle-feeding  plants 
where  corn  silage  is  used  extensively,  cattle  often  receive  some  more 
or  less  moldy  silage,  and  in  many  cases  are  allowed  to-  pick  over  with 
impunity  the  refuse  from  the  tops  of  newly-opened  silos.  Certainly 
the  number  of  outbreaks  of  this  disease  in  cattle  is  irrelative  to  the 
primary  occurrence  of  molds  upon  animal  feeds. 

FEEDING  TESTS  WITH  CORN  SILAGE  SUSPECTED  OF 
CAUSING  FORAGE  POISONING  IN  CATTLE 

The  series  of  investigations  reported  herein  was  started  at  the 
University  after  an  outbreak  of  forage  poisoning  had  occurred 
among  twenty  experimental  calves  during  the  winter  of  1915-16. 
These  calves  consisted  of  steers  and  heifers,  coming  yearlings  that 
were  being  fed  in  two  lots  of  ten  each  in  a  test  (known  as  Experi- 
mental Project  229)  to  determine  the  relative  efficiency  of  feeding 
grain  according  to  appetite  and  in  feeding  it  in  restricted  amounts 
with  silage  as  the  sole  roughage.  The  plan  of  this  experiment  was 
to  feed  each  of  the  two  lots  the  following  rations.  Lot  1 :  shelled 
corn  5  parts,  and  cottonseed  meal  1  part,  according  to  appetite; 
silage  to  be  fed  in  such  amounts  as  would  not  restrict  the  calves' 
appetite  for  concentrates.  Lot  2  was  to  receive  the  same  grain  mixture 
as  Lot  1,  but  the  amount  was  to  be  restricted  to  that  barely  necessary 
to  obtain  satisfactory  gains ;  corn  silage  to  be  fed  ad  libitum  to  this 
lot. 

For  some  time  prior  to  the  first  of  January,  1916,  it  had  been 
evident  that  a  few  calves  in  each  lot  were  doing  poorly.  They  were 

163 


164  BULLETIN  No.  210 


f  June, 


unthrifty  in  appearance,  ate  very  sparingly,  and  made  unsatisfactory 
gains.  On  December  16,  No.  35,  a  calf  in  Lot  1,  was  found  dead 
about  two  hours  after  the  lot  received  its  morning  feed.  It  was 
thought  that  she  had  slipped  on  the  sleety  pavement  and  broken 
her  neck,  as  her  head  was  doubled  back  under  her  body.  Even  in 
the  light  of  subsequent  developments,  it  appears  unlikely,  altho  pos- 
sible, that  death  may  have  occurred  during  convulsions  accompany- 
ing an  attack  of  forage  poisoning.  On  January  26,  No.  38,  a  Here- 
ford heifer  in  Lot  2,  died  in  a  tonic  spasm,  which  undoubtedly  was 
due  to  forage  poisoning.  Unlike  Calf  No.  35,  No.  38  had  shown 
symptoms  of  unthriftiness  for  at  least  a  month  previous  to  death. 
During  this  time  she  had  been  more  or  less  stiff  and  her  appetite  was 
poor.  The  stiffness  gradually  increased  until  the  evening  of  the  25th. 
She  was  down  on  the  morning  of  January  26,  and  convulsions  pre- 
ceded death  about  noon. 

During  the  month  of  January,  seven  calves  were  observed  to  bo 
very  unthrifty,  showing  marked  stiffness  in  moving,  loss  of  appetite, 
and  a  falling  off  of  gains.  When  these  unthrifty  animals  were  ex- 
cited, as  would  happen  on  weigh  days  or  when  the  men  were 
cleaning  the  manure  from  the  lots,  the  stiffness  seemed  to  be  aggra- 
vated, their  eyes  became  starey,  and  they  exhibited  a  terrified 
appearance.  Several  times  on  such  occasions,  individual  calves  were 
suddenly  seized  with  tonic  convulsions,  followed  by  complete  loss 
of  locomotion.  A  calf  thus  affected  would  stand  for  a  moment  or 
two  with  fore  feet  wide  apart  as  if  trying  to  brace  itself,  mouth 
open,  tongue  slightly  extended  as  if  about  to  cough,  and  then  gradu- 
ally lean  backward  until  it  fell  to  the  ground  and  lay  broadside 
with  feet  extended,  presenting  an  appearance  resembling  death  rigor. 
This  condition  would  last  from  a  few  seconds  to  a  few  minutes,  when 
the  calf  would  relax,  slowly  revive,  and  assume  a  normal  attitude. 
These  nervous  manifestations,  involving  the  voluntary  muscles,  were 
accompanied  by  profuse  salivation,  a  lateral  movement  of  the  jaws, 
and  difficulty  in  breathing.  These  unthrifty  calves,  when  excited, 
would  often  show  evidence  of  impaired  vision  by  running  or  walking 
into  fences,  against  the  feed  bunks,  or  against  other  calves  in  the 
lot,  without  falling  or  suffering  from  tonic  spasms.  While  in  this 
condition,  they  would  show  extreme  stiffness,  muscular  tremors  in 
the  limbs,  and  general  nervousness. 

On  March  11,  it  was  so  evident  that  the  object  of  the  experiment 
could  never  be  realized  because  of  the  unthriftiness  and  nervous 
derangement  of  so  many  of  the  calves,  that  it  was  decided  to  aban- 
don the  project  and  use  the  calves  in  an  attempt  to  determine  whether 
any  of  the  feeds  were  responsible  for  the  abnormal  condition  de- 
scribed. This  test  (known  as  Project  229a)  was  conducted  according 
to  the  following  plan. 


1018] 


FORAGE  POISONING  IN  CATTLE  AND  HORSES 


165 


TEST  AT  ILLINOIS  EXPERIMENT  STATION  TO  DETERMINE  FEEDS 
RESPONSIBLE  FOR  UNTHRIFTINESS  OE  CALVES 

Plan. — Six  normal  and  six  abnormal  calves  were  selected  from  the 
animals  used  in  Project  229  and  divided  into  six  lots;  each  lot  con- 
tained one  thrifty  and  one  unthrifty  animal.  The  rations  fed  to  the 
respective  lots  consisted  of  the  feeds  indicated  by  the  following  tabu- 
lation and  in  addition  5  parts  of  shelled  corn: 

Lot  1  Cottonseed  meal  1  part,  silage  6  parts 

Lot  2  Cottonseed  meal  1  part,  alfalfa  hay 

Lot  3  Linseed  oil  meal  1  part,  silage  6  parts 

Lot  4  Linseed  oil  meal  1  part,  moldy  silage  6  parts 

Lot  5  Cottonseed  meal  2  parts,  silage  7  parts 

Lot  G  Cottonseed  meal  2  parts,  alfalfa  hay 

Method  of  Feeding. — All  animals  were  fed  individually  in* stalls. 
Those  receiving  silage  had  the  grain  and  silage  thoroly  mixed  to- 
gether before  feeding.  Hay  Was  fed  in  the  same  manger  as  the  grain 
but  not  mixed  with  it.  All  refused  feed  was  weighed  back  before  the 
following  feed  was  given.  All  cattle  were  fed  according  to  appetite. 

Equipment. — Two  units  of  the  old  cattle-feeding  plant  were  used. 
This  plant  consists  of  a  long,  low  shed  12  feet  deep  and  open  on  the 
south.  Each  unit  is  36  feet  long  and  opens  on  a  36x48-foot  paved  lot. 
One-half  of  each  of  these  two  units  was  divided  into  six  stalls,  in 
which  the  calves  were  fed  individually.  The  calves  were  confined  in 
the  stalls  at  feeding  time  by  means  of  a  heavy  chain  hooked  across 
the  rear  of  each  stall.  Approximately  two  hours  after  feeding,  the 
calves  were  turned  out  pf  the  stalls  and  allowed  to  run  together  in 
the  remaining  half  of  the  shed  and  pen.  Lots  1,  2,  and  3  were  kept 
in  the  east  unit  and  Lots  4,  5,  and  6,  in  the  unit  next  to  the  west. 

Cattle: 


Calf  No. 

Weight 

Previous  treatment 

Ibs. 

Lot  1 

40 

885 

Light  grain  ration 

23 

665 

Heavy  grain  ration 

•1 

Lot  2 

6 

725 

Light  grain  ration 

36 

465 

Light  grain  ration 

Lot  3 

28 

825 

Heavy  grain  ration 

8 

575 

Heavy  grain  ration 

Lot  4 

11 

795 

Heavy  grain  ration 

.      27 

645 

Heavy  grain  ration 

Lot  5 

21 

745 

Light  grain  ration 

39 

635 

Heavy  grain  ration 

Lot  6 

13 

790 

Heavy  grain  ration 

34 

595 

Heavy  grain  ration 

165  BULLETIN  No.  210  [June, 

This  experiment  was  started  on  March  11,  1916,  and  concluded 
July  8,  1916. 

A  study  of  the  foregoing  outline  will  show  that  an  attempt  was 
made  to  determine  by  a  process  of  elimination  the  feed  responsible 
for  the  condition  described.  Lot  1  received  the  same  feed  mixture 
that  was  fed  in  Project  229.  In  Lot  2,  alfalfa  was  substituted  for 
corn  silage.  In  Lot  3,  linseed  oil  meal  was  substituted  for  cottonseed 
meal,  the  roughage  remaining  unchanged.  In  Lot  4,  the  cottonseed 
meal  was  replaced  by  linseed  oil  meal  and  the  roughage  consisted  ex- 
clusively of  moldy  silage.  Lot  5  received  a  double  allowance  of  cot- 
tonseed meal  with  silage  as  the  roughage.  Lot  6  received  a  double 
allowance  of  cottonseed  meal  with  alfalfa  as  the  roughage.  It  was 
felt  that  if  the  unthrifty  condition  was  due  to  the  accumulative  effect 
of  long-continued  feeding  of  cottonseed  meal,  Lots  1,  2,  5,  and  6  might 
provide  some  positive  evidence  on  this  point,  and  Lot  3,  and  possibly 
Lot  4,  might  be  expected  to  give  negative  results.  If  the  silage  were 
primarily  involved,  then  Lots  1,  3,  4,  and  5  might  give  positive  re- 
sults, and  the  remaining  lots  negative  results.  If  it  were  moldy  silage, 
then  Lot  4  might  be  expected  to  give  positive  results,  and  Lots  2  and  6 
negative  results.  It  may  be  significant  that  the  calves  were  bedded 
with  straw  during  the  progress  of  Project  229,  while  shavings  were 
used  for  bedding  in  the  forage-poisoning  test.  A  general  summary 
of  the  results  from  March  11  to  July  8  is  contained  in  Table  1. 

A  study  of  this  table  shows  that  in  no  case  did  a  calf  that  was 
unthrifty  at  the  beginning  of  the  test  consume  as  much  feed  as  any 
one  of  the  calves  that  was  thrifty  when  the  .test  was  started. 

Considering  the  length  of  time  that  these  cattle  had  been  on  feed 
when  this  test  was  started,  and  the  season  of  the  year  during  which 
it  was  conducted,  the  gains  made  by  the  calves  that  were  thrifty  at 
the  start  were  entirely  satisfactory,  with  the. possible  exception  of  the 
gains  made  by  No.  11,  a  heifer  that  received  spoiled  silage  as  her  sole 
roughage.  However,  this  heifer  could  not  have  been  considered  un- 
thrifty in  spite  of  the  fact  that  she  gained  only  .76  pound  per  day. 
She  carried  a  good  finish  and  was  in  excellent  thrift,  as  shown  by 
her  general  appearance  at  the  end  of  the  test.  In  fact,  there  was  a 
general  improvement  in  every  animal,  with  the  possible  exception  of 
No.  27.  This  steer  suffered  from  malnutrition  during  the  test  and  his 
joints  were  badly  swollen  at  times,  but  even  he  was  not  at  his  worst 
at  the  close  of  the  experiment,  and  at  no  time  during  the  test  did  he 
show  symptoms  suggestive  or  diagnostic  of  forage  poisoning  such  as 
were  exhibited  by  this  and  other  calves  before  the  trial  was  inaugu- 
rated. 

The  data  collected  in  this  test  and  the  reaction  of  these  calves  to 
the  rations  used  do  not  warrant  any  conclusion  regarding  the  identity 
of  the  feed  harboring  the  causative  agent  of  disturbances  observed  in 
these  calves  during  the  progress  of  Project  229. 


1918] 


FORAGE  POISONING  IN  CATTLE  AND  HORSES 


167 


TABLE  1. — FEED  CONSUMPTION  AND  GAINS  IN  TEST  TO  DETERMINE  THE  FEED 
RESPONSIBLE  FOR  UNTHRIFTINESS  OF  CALVES  (PROJECT  229a) 
March  11— July  8,  1916 


Calf 
No, 

Feeds 

Total  feed 
consumed 

Daily 
feed 

Total 
gain 

Daily 
gain 

Ibs. 

Wa. 

Ibs. 

Ibs. 

Lot  1 

40 

Corn 

1469.75 

12.34 

225 

1.89 

C.  S.  M. 

294.50 

2.47 

Silage 

1767.35 

14.85 

33 

Corn 

920.16 

7.73 

140 

1.18 

C.  S.  M. 

181.89 

1.53 

Silage 

1101.45 

9.26 

Lot  2 

G 

Corn 

1481.60 

12.45 

220 

1.85 

C.  S.  M. 

297.40 

2.50 

Alfalfa 

349.90 

2.94 

36 

Corn 

846.83 

7.12 

105 

0.88 

C.  S.  M. 

170.27 

1.43 

Alfalfa 

170.05 

1.43 

Lot3 

28 

Corn 

1152.90 

9.70 

165 

1.39 

Oil  meal 

231.50 

1.95 

Silage 

1390.90 

11.69 

8 

Corn 

677.75 

5.69 

85 

0.71 

Oil  meal 

135.75 

1.14 

Silage 

755.95 

6.38 

Lot  4 

11 

Corn 

1085.80 

9.12 

90 

0.76 

Oil  meal 

218.15 

1.83 

Bad  silage 

1237,30 

10.40 

27 

Corn 

792.20 

6.65 

40 

0.34 

Oil  meal 

159.35 

1.34 

Bad  silage 

871.65 

7.28 

Lot5 

21 

Corn 

1224.10 

10.29 

245 

2.06 

C.  S.  M. 

496.15 

4.17 

Silage 

1712.38 

14.39 

39 

Corn 

859.72 

7.22 

165 

1.39 

C.  S.  M. 

342.43 

2.88 

Silage 

1194.50 

10.04 

Lot  G 

13 

Corn 

1219.75 

10.25 

190 

1.60 

C.  S.  M. 

487.85 

4.10 

Alfalfa 

399.45 

3.36 

34 

Corn 

803.36 

6.75 

125 

1.05 

C.  S.  M. 

319.14 

2.68 

Alfalfa 

199.07 

1.67 

153 


BULLETIN  No.  210 


[June, 


A  FEEDING  TEST  WITH  SUSPECTED  SILAGE  AT  HARRISTOWN,  ILLINOIS 

Shortly  after  the  foregoing  project  was  started,  Charles  Ach,  of 
Harristown,  Illinois,  notified  the  University  of  the  loss  of  several  com- 
ing yearling  pure-bred  Herefords  and  a  few  older  cattle  from  illness 
resembling  forage  poisoning.  Here  again,  silage  was  the  suspected 
feed.  Upon  the  request  of  Mr.  Ash,  representatives  from  the  Univer- 
sity visited  the  farm  and  examined  the  silage  and  other  feeds  used. 
A  preliminary  examination  of  the  feeds  revealed  nothing  that  might 
be  suspected  except  a  very  little  mold  in  small  areas  in  the  silo.  The 
silage,  as  a  whole,  was  judged  to  be  good. 

With  the  cooperation  of  Mr.  Ash,  it  was  decided  to  conduct  a  test 
upon  his  farm  supplementary  to  the  one  under  way  at  the  University. 
This  test  was  conducted  according  to  the  following  outline: 

Plan. — One  lot  of  five  choice  yearling  steers  and  one  lot  of  plain 
bull  calves  were  fed  a  ration  of  the  suspected  corn  silage,  linseed  oil 
meal,  and  water. 

Cattle. — Five  choice  Hereford  yearling  steers  were  purchased  from 
Mr.  Ash,  and  five  pure-bred  Holstein  bull  calves  dropped  the  preced- 
ing fall  were  purchased  from  the  Dairy  Department,  University  of 
Illinois.  The  calves  had  been  used  on  a  milk-substitute  experiment 
and  did  not  shoAv  the  thrift  and  bloom  that  the  yearlings  possessed. 
The  average  initial  weight  of  the  Herefords  was  675  pounds,  and  the 
average  initial  weight  of  the  calves  was  242  pounds. 

TABLE  2. — FEEDING  TEST  WITH  SUSPECTED  SILAGE  AT  HARRISTOWN,  ILLINOIS 


Initial 
date 
(1916) 

Final  date 

Days 

Total 
initial 
weight 

Final 
weight 

Gain 

Ave. 
daily 
gain 

Silage 

Oil 
meal 

Lot  1 — Holstein  Calves 


Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

May  10 

May  24 

14 

1210 

1290 

80 

1.14 

1060 

26.50 

May  24 

June  28 

35 

1290 

1490 

200 

1.14 

3130 

78.25 

June  28 

July   5 

7 

1490 

1480 

-10 

(-) 

660 

16.50 

July   5 

July  19 

14 

1480 

1525 

45 

.643 

2010 

50.25 

Lot  2 — Hereford  Yearlings 


May    10 

May    24 

13^ 

3375 

3520 

145 

2.14 

1966.20 

49.30 

May    24 

June    28 

35 

3520 

3915 

395 

2.25 

6694.63 

167.37 

June    28 

July       5 

7 

2915 

3900 

-15 

(-) 

1400.00 

35.00 

July       5 

July     19 

14 

3900 

3970 

70 

1.0 

2910.00 

72.75 

All  of  the  cattle  made  satisfactory  gains;  in  fact,  the  Herefords 
yielded  a  profit  on  the  operation  after  all  expenses  were  deducted.  The 
Holstein  calves  were  not  as  thrifty  at  the  start  and  did  not  make  as 
satisfactory  gains  as  the  Herefords. 

During  the  late  summer  of  1916,  a  further  test  was  made  at 
Ottawa,  Illinois.  In  this  test  three  two-year-old  steers,  one  cow,  and 


1918]  FORAGE  POISONING  IN  CATTLE  AND  HORSES  169 

two  sucking  calves  were  fed  corn  silage  which  had  been  experimentally 
proved  capable  of  inducing  a  fatal  type  of  forage  poisoning  when 
consumed  by  horses.  One  calf  died  during  the  experiment,  but  death 
was  attributed  to  causes  other  than  forage  poisoning.  As  in  the 
other  field  tests  with  cattle,  typical  symptoms  of  forage  poisoning 
were  not  produced  by  the  experimental  ration. 

The  results  of  these  investigations  seem  to  indicate  that  most  cattle 
are  not  so  susceptible  to  forage  poisoning  as  are  horses  and  mules,  and 
that  contaminated  corn  silage,  and  possibly  other  animal  feeds 
which  are  unsafe  or  fatal  to  horses,  may  be  fed  with  less  danger 
to  cattle.  This  deduction  is  in  accord  with  the  observations  of  Gra- 
ham, Brueckner,  and  Pontius,  in  a  remote  outbreak  of  forage  poison- 
ing,1 where  the  disease  was  produced  in  a  horse  and  the  cattle 
appeared  to  be  non-affected.  However,  the  evidence  from  many 
outbreaks  leads  the  authors  to  suspect  that  some  cattle  are  more 
susceptible  than  others  and  that  damaged  or  otherwise  contaminated 
corn  silage,  or  possibly  other  feeds,  may  in'  some  instances  produce 
fatal  results  in  cattle  following  ingestion. 

• 

REPORT  OF  FORAGE  POISONING  INVESTIGATIONS  WITH 
HORSES  AT  OTTAWA,  ILLINOIS 


During  the  month  of  June,  1916,  an  outbreak  of  forage  poisoning 
occurred  among  horses  on  the  farm  of  Alexander  McLean,  near 
Ottawa,  Illinois.  This  disease  was  reported  to  the  University  by  Mr. 
I.  S.  Brooks,  County  Adviser  for  LaSalle  county.  Upon  investigation, 
it  was  learned  that  Mr.  McLean  had  fed  silage  to  his  horses  during 
the  late  winter  and  spring  months  but  had  discontinued  the  use  of 
silage  during  the  early  part  of  the  summer  while  the  pastures  were 
good.  Some  time  in  June,  after  the  pastures  began  to  fail,  the  silo 
was  reopened,  and  the  feeding  of  silage  to  both  horses  and  cattle  was 
resumed.  Some  of  the  spoiled  silage  removed  from  the  silo  when  it 
was  reopened,  was  used  as  bedding  for  both  horses  and  cattle.  Within 
three  or  four  days  after  the  use  of  silage  was  resumed,  symptoms  of 
forage  poisoning  were  observed  in  certain  of  the  horses  and  two  mules. 
Eight  or  nine  head  of  horses  in  all  were  affected  and  six  died.  Dr. 
Fowlie,  the  local  veterinarian  who  attended  these  cases,  described  the 
symptoms  as  typical  of  forage  poisoning.  An  inspection  of  the  feeds 
used  and  the  history  of  the  outbreak  led  the  authors  strongly  to  sus- 
pect silage  as  the  contaminated  feed,  but  the  evidence  was  not  con- 
clusive, as  cattle  receiving  feed  from  the  same  silo  had  shown  no 
symptoms  of  the  disease  and  some  of  the  other  feeds  which  had  been 
fed  to  the  horses  were  not  entirely  free  from  molds;  hence  it  was 

'Ky.  Exp.  Sta.  Bui.  208. 


170  BULLETIN  No.  210  [June, 

decided  to  attempt  to  secure  some  positive  evidence  in  regard  to  the 
role  silage  played  in  this  outbreak. 

Five  horses  were  purchased  in  the  vicinity  of  Ottawa  and  put  on 
a  ration  of  the  suspected  silage,  wholesome  corn,  and  water,  at  the 
McLean  farm  on  June  28,  1916.  One  horse  began  to  show  symptoms 
of  forage  poisoning  on  the  third  day  and  died  on  the  fourth.  Another 
went  down  on  July  2  and  died  on  July  4.  Another  was  killed  on  July 
8,  after  showing  pharyngeal  paralysis  for  four  days  and  consuming 
no  feed  or  water  for  that  length  of  time.  The  two  remaining  horses 
survived  considerably  longer,  but  all  five  were  dead  by  the  end  of  the 
third  week.  One  of  Mr.  McLean's  horses  was  used  as  a  control  and 
fed  corn  from  the  same  source  as  that  used  in  the  test,  with  negative 
results. 

The  symptoms  of  forage  poisoning,  as  exhibited  by  the  horses  af- 
fected in  these  tests,  were  uniform  and  pronounced.  The  most  char- 
acteristic symptom  was  paralysis  of  the  throat.  One  of  the  first  mani- 
festations of  the  disease-  was  the  inability  of  the  affected  horse  to 
drink.  Prolonged  efforts  were  made  to  drink  but  to  no  avail.  This 
condition  is  often  overlooked  where  horses  obtain  their  water  from 
tanks  so  large  that  it  is  difficult  or  Impossible  to  tell  whether  or  not 
the  water  has  actually  been  lowered.  In  fact,  under  such  conditions, 
the  observer  may  get  the  impression  that  the  horse  is  drinking  ab- 
normally large  amounts  when  in  reality  he  is  swallowing  very  little 
or  none.  However,  when  allowed  access  to  water  in  a  bucket,  affected 
animals  made  prolonged  efforts  to  drink  without  perceptibly  lowering 
the  water.  Some  were  able  to  eat  from  one  to  three  or  four  days  after 
they  were  unable  to  drink.  Our  observations  were  that  affected  animals 
soon  became  unable  to  swallow  feed  as  well  as  water.  The  appetites 
remained  normal.  Many  of  the  horses  continued  to  masticate  feed  as 
long  as  they  could  stand,  but  this  masticated  feed  mixed  with  saliva 
dribbled  from  their  mouths,  due  to  their  inability  to  swallow.  The 
other  characteristic  symptoms  were  profuse  salivation  and  lack  of 
muscular  coordination.  In  the  opinion  of  those  connected  with  this 
feeding  test,  the  results  clearly  established  the  fact  that  the  silage  was 
the  source  of  the  poisoning.  An  autopsy  was  held  on  each  horse  and 
bacteriological  cultures  were  made  from  various  organs  of  all  the 
horses  as  well  .as  from  the  feed. 

Three  steers,  a  cow,  and  two  calves,  were  fed  experimentally  for 
several  weeks  on  a  ration  composed  exclusively  of  this  silage  and 
water,  without  producing  any  noticeable  symptoms  of  forage  poison- 
ing. These  results  correspond  with  the  previous  experience  of  the 
authors  in  trying  to  induce  the  disease  in  cattle,  reported  in  the  first 
part  of  this  bulletin;  and  taken  in  conjunction  with  results  of  previ- 
ous tests  they  indicate  that  cattle  arc  much  less  susceptible  to  the 
disease  than  are  horses.  However,  the  history  of  several  outbreaks 


I!)  IS] 


FORAGE  POISONING  IN  CATTLE  AND  HORSES 


171 


of  an  apparently  similar  disease  among  cattle  leads  to  a  strong*  be- 
lief that  contaminated  silage  may  sometimes  cause  forage  poisoning 
in  this  class  of  animals. 

At  the  University  of  Illinois,  the  bacteriological  examination  of 
the  feed,  as  well  as  the  cultures  made  from  the  organs  of  the  dead 
horses,  failed  to  reveal  any  organism  that  could  be  considered  the 
causative  agent  of  forage  poisoning.  However,  Dr.  Robert  Graham, 
formerly  of  the  University  of  Kentucky  but  now  connected  with  the 
University  of  Illinois,  whose  services  had  been  secured  in  an  advisory 
capacity  on  this  project,  took  samples  of  the  silage  to  his  laboratory 
at  the  Kentucky  Experiment  Station,  where  he  was  able  to  isolate  an 
organism  corresponding  very  closely  to  one  he  had  isolated  from  an 
oat  hay  which  had  been  proved  to  be  the  source  of  an  outbreak  of 
forage  poisoning  in  Kentucky.  Graham,  Brueckner,  and  Pontius, 
working  at  the  University  of  Kentucky  independently  of  Rusk  and 
Grindley,  developed  a  serum  that  in  laboratory  tests  protected 
against  fatal  doses  of  broth  cultures  of  the  organisms  isolated  from 
both  of  these  sources,  as  well  as  from  similar  organisms  isolated  from 
other  animal  feeds. 

In  the  meantime,  the  University  of  Illinois  purchased  the  silage 
remaining  in  the  McLean  silo  with  the  understanding  that  the  silo 
would  be  refilled  and  as  soon  as  it  was  fed  down  to  the  point  where 
the  contaminated  silage  commenced,  the  University  would  be  given 
an  opportunity  to  conduct  further  experiments.  A  circular  oilcloth 
cover  made  to  fit  the  silo  marked  the  division  between  the  new  and 
the  old  silage.  When  this  point  in  the  silo  was  reached,  arrangements 
were  made  to  give  the  serum  mentioned  a  field  trial  against  the  McLean 
silage.  Accordingly,  on  June  13,  1917,  eight  horses  that  had  been 
purchased  on  the  Chicago  market,  were  started  on  a  ration  of  this 
silage,  'wholesom'e  corn,  and  water.  Five  of  these  horses  received 
intravenous  injections  of  the  Botulinus  antitoxin  and  three  were  left 
as  controls  without  serum.  The  summary  of  this  test  is  shown  in 
Table  3. 

TABLE  3. — SECOND  FEEDING  TRIAL  WITH  HORSES  AT  THE  MOL/EAN  FARM 
June  13— July  12,  1917 


Horse 
No. 

Scrum 

Silage 
fed 

Silage 
refused 

Silage 
consumed 

Silage 
consumed 
per  day 

Days 

without 
feed 

1  )ays 
without 
water 

Date 
died 

Ibs. 

Ibs. 

Ibs. 

Ibs.  - 

1 

None 

445.5 

136.75 

308.75 

22.87 

6.5 

10.0 

July     3 

2 

Serum 

996.5 

366.0 

630.5 

21.02 

None 

None 

3 

Serum 

523.5 

294.5 

229.0 

16.96 

8.5 

1.0 

July     5 

4 

Serum 

835  .  5 

406.5 

409.0 

13.63 

None 

None 

5 

None 

287.5 

101.0 

186.5 

26.64 

2.5 

3.5 

June  22 

6 

Serum 

1188.0 

477.5 

710.5 

23.68 

None 

None 

7 

Serum 

1308.5 

336.0 

972.5 

32.41 

None 

None 

8 

None 

247.0 

78.5* 

168.5 

21.06 

4.0 

4.0 

June  23 

172  BULLETIN  No.  210  [June, 

In  this  table  no  account  is  taken  of  the  corn  fed,  as  the  horses  re- 
ceived a  uniform  amount  of  6  pounds  of  ear  corn  per  head  per  day, 
and  practically  none  was  refused.  The  consumption  of  silage  varied 
a  great  deal  with  individuals,  ranging  from  13.63  pounds  per  day  in 
the  case  of  No.  4  to  32.41  pounds  per  day  for  No.  7.  It  will  be  noticed 
from  the  foregoing  tabulation  that  all  of  the  control  horses  died  in 
from  91/2  to  20  days  after  the  beginning  of  the  experiment.  All  of 
the  scrum  horses  came  thru  in  excellent  condition  except  No.  3,  a 
horse  that  was  clearly  off  from  the  second  day  of  the  experiment.  On 
that  day,  Dr.  Fowlie,  of  Ottawa,  who  gave  this  test  a  great  deal  of 
his  personal  attention,  stated  that  in  his  opinion  this  horse  had  been 
"drugged"  before  he  left  the  Chicago  yards,  and  that  he  was  suffer- 
ing from  an  overdose.  At  different  times  during  the  test,  this  horse 
showed  symptoms  of  colic,  a  condition  not  observed  in  any  of  the 
horses  'suffering  from  forage  poisoning.  Dr.  Fowlie,  on  two  or  three 
occasions,  gave  this  horse  purgatives  with  indifferent  results.  From 
June  26  until  he  died,  this  horse  ate  little  or  no  feed.  During  this 
time,  he  received  141  pounds  of  silage  and  refused  all  but  9  pounds. 
This  difference  of  9  pounds  was  probably  due  as  much  to  error  in 
weighing  and  drying  out  of  the  silage  as  to  actual  consumption  by 
the  horse.  He  died  on  July  5,  and  upon  post-mortem  examination  it 
was  found  that  his  caecum  was  ruptured,  accompanied  by  diffuse 
peritonitis.  His  death  was  thought  not  to  be  due  in  any  way  to  forage 
poisoning. 

While  the  foregoing  table  makes  no  mention  of  the  fact,  the  feed 
records  taken  contain  a  complete  record  of  water  drunk  and  of  tem- 
peratures taken  twice  daily.  A  study  of  these  temperature  data  did 


FIG.  1. — HORSE  No.  9  JTST  BEFORE  DEATH.    NOTE  PENDULANT  CONDITION  OF  THE 
TONGUE,  DUE  TO  PARALYSIS 


W18] 


FORAGE  POISONING  IN  CATTLE  AND  HORSES 


173 


FIG.  2. — BOTTOM  OF  MANGER  OF  HORSE  No.  5,  SHOWING  PARTLY  MASTICATED  FEED 
MIXED  WITH  SALIVA,  WHICH  HAD  DRIBBLED  FROM  HIS  MOUTH 


FIG.  3.— HORSES  Nos.  2,  4,  6,  AND  7,  ON  JULY  12,  1917 


174 


BULLETIN  No.  210 


[June, 


not  reveal  any  characteristic  or  consistent  fluctuation  from  the  normal 
and  the  data  therefore  were  not  tabulated. 

Horses  Nos.  6  and  7  were  worked  regularly  during  the  last  few 
days  of  the  test,  in  order  to  determine  whether  or  not  this  ration  was 
sufficient  to  maintain  them  at  hard  work.  Each  horse  was  hitched 
with  one  of  Mr.  McLean's  and  given  a  full  day's  work  in  cultivating 
corn.  No.  6  gave  an  unplanned-for  exhibition  of  her  superabundant 
energy  on  the  second  day  that  she  was  worked  by  taking  the  leading 
part  in  a  spirited  runaway. 

To  make  a  further  and  more  comprehensive  study  of  the  prophy- 
lactic properties  of  the  immune  sera,  another  test  was  started  on  June 
24  with  ten  head  of  horses.  These  horses  received  nothing  but  con- 
taminated corn  silage  and  water,  no  corn  being  fed  and  no  bedding 
used.  The  serum  treatment  of  these  horses  is  shown  in  Table  4  and 
a  summary  of  the  feeds  eaten  and  the  gains  made  are  shown  in  Table  5. 

TABLE  4. — SERUM  TREATMENT  OF  HORSES  IN  THIRD  FEEDING  TRIAL  AT 

MCLEAN  FARM 
June  24— July  12,  1917 


Horse  No. 
and  treatment 

June  24, 
2:30  p.m. 

July  3 

July  5 

July  6 

9  —  None 



Died 

10—  G.  M. 

40  cc. 
intra. 

40  cc. 
sub. 

40  cc. 
sub. 

Lived 

11—  S.  G. 

40  cc. 
intra. 

40  cc. 
sub. 



Lived 

12—  S.  G. 

40  cc. 
intra. 



Lived 

13—  G.  M. 

40  cc. 
intra. 

40  cc. 
sub. 

40  cc. 
sub. 



Lived 

14—  G.  M. 

40  cc. 
intra. 







Lived 

15—  H.  0. 

40  cc. 
intra. 

( 

40  cc. 
intra. 

Lived 

16—  H.  O. 

40  cc. 
intra. 



Lived 

17—  H-91 

40  cc. 
intra. 

40  cc. 
intra. 

Lived 

18—  H-91 

40  cc. 
intra. 

Lived 

G.  M.=Goat  serum  immune  to  pathogenic  bacillus  isolated  from  McLean  silage. 

S.  G.= Sheep  serum  immune  to  pathogenic  bacillus  isolated  from  Gaines  silage. 

H.  O.=Horse  serum  immune  to  pathogenic  bacillus  isolated  from  Griffith  oat 
water. 

H-91=Horse  serum  immune  to  pathogenic  bacillus  isolated  from  cecum  of 
Horse  91. 


191 S] 


175 


TABLE  5. — SUMMARY  OF  DATA  FROM  THIRD  FEEDING  TRIAL  WITH  HORSES  AT  THE 

MCLEAN  FARM 
June  24— July  12;  1917 


Gain 

Horse 
No. 

Serum 

Silage 
fed 

Silage 
refused 

Silage 
cunsumed 

Silage 
consumed 
per  day 

Initial 
weight 

Final 
weight 

or 

loss 

/6s. 

/6s. 

/6s. 

/6s. 

/6s. 

/6s. 

/6s. 

9 

None 

819.0 

75.0 

744.0 

46.50 

1125 

Died1 

10 

Serum 

578.0 

119.  -5 

458.5 

25.47 

875 

830 

—45 

11 

726.0 

53.0 

673.0 

37.39 

1150 

1120 

—30 

12 

651  .  5 

123.5 

528.0 

29.33 

1050 

1010 

—40' 

13 

692.5 

99.0 

593.5 

32.97 

1025 

975 

—50 

14 

650.5 

113.5 

596.0 

33.11 

875 

830 

—45 

15 

697.0 

75.0 

602.0 

33.44 

825 

815 

—10 

16 

713.5 

37.0 

676.5 

37.58 

1080 

1125 

+45 

17 

731.0 

54.5 

676.5 

37.58 

1100 

1090 

—10 

18 

685.0 

77.5 

607.5 

33.75 

950 

930 

—20 

^o.  9  died  July  12,  having  lived  two  days  without  water  and  feed. 

It  will  be  noted  that  all  but  one  of  these  horses  received  serum. 
This  horse  developed  typical  symptoms  of  forage  poisoning  and  died 
on  July  12.  None  of  the  other  horses  at  any  time  exhibited  symptoms 
of  forage  poisoning.  They  were  continued  on  this  ration  until  after 
the  morning  feed  on  Sunday,  July  15,  at  which  time  the  silage  was 
practically  gone  and  its  use  had  to  be  abandoned.  While  only  one 
of  these  horses  maintained  his  weight  on  a  ration  of  corn  silage  and 
water,  the  losses  were  not  significant,  and  in  all  probability  most 
of  these  horses  would  have  regained  their  initial  weight  if  the  ex- 
periment could  have  been  continued  a  month  longer. 


FIG.  4. — HORSES  IN  THIRD  FEEDING  TRIAL  AT  MCLEAN  FARM. 

BIGHT  TO  LEFT 


NOS.  9  TO  18,  FROM 


176  BULLETIN  No.  210 

The  results  of  these  two  tests  at  the  McLean  farm  lead  the  authors 
to  believe  that  these  sera  protected  the  horses  against  forage  poisoning 
caused  by  the  organism  responsible  for  the  McLean  outbreak.  Of 
course  it  is  not  contended  that  all  outbreaks  of  forage  poisoning  among 
horses  are  caused  by  this  or  similar  organisms,  but  the  results  of  this 
experiment  apparently  justify  a  trial  of  this  serum  in  cases  of  similar 
outbreaks. 


The  authors  wish  to  acknowledge  their 'indebtedness  to  Drs.  Gra- 
ham, Brueckner,  and  Pontius,  of  the  Kentucky  Agricultural  Experi- 
ment Station,  for  the  opportunity  of  using  the  various  sera  which  they 
had  developed,  and  also  for  valuable  suggestions.  The  authors  also 
wish  to  acknowledge  their  indebtedness  to  Mr.  H.  C.  Eckstein,  Assis- 
tant in  Animal  Nutrition,  and  Dr.  J.  A.  Sperry,  Associate  in  Bacteri- 
ology, who  aided  very  much  in  the  experimental  work. 


UNIVERSITY  OF  ILLINOIS-URBANA 


